Territorija Neftegas № 6 2016

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Anticorrosive protection

General patterns of stress corrosion cracking of steel, which has a decisive influence on the possibility of using casing and tubing for the production of hydrocarbons at high concentrations of carbon dioxide are described. The problems of carbon dioxide corrosion of well equipment at the Bovanenkovo and Urengoy oil, gas condensate fields, which is very dangerous for the well equipment, are considered. A method of laboratory studies for fragments of pipe defects in the form of pits on the inner surface and through holes is proposed. The results of studies of pipes metal are considered. The results of metallographic examination of the pipe material subjected to pitting carbon dioxide corrosion are presented. The causes and mechanisms of carbon dioxide corrosion destruction of the pipe body are analysed. In order to prevent carbon dioxide corrosion propositions for the use of casing and tubing made of martensitic steel containing 13% chromium were submitted. Technical requirements for casing and tubing made of martensitic steel containing 13% chromium are formulated.

Automation

﻿﻿﻿﻿﻿﻿Hydrating is a great problem for a gas-field gathering system specially for high north’s gas foundations. Hydrating depends on pressure-temperature conditions, gas composition and specific humidity of gas. Hydrating occurs at any stage of reservoir development, so it’s very important to establish non hydrating regime. This regime is achieved by well injection of hydrate growth inhibitor. As usual it is methanol. There are many known methods of injection, but they don’t provide real time optimalization of methanol flow rate. This is caused by difficulties of collecting measuring information for calculation and by difference in operation processes of wells, pipelines and collectors. Methanol underconcentration makes it from inhibitor to catalyzator. That’s why surplus amount of methanol is given to the well. It is offered in the article to count methanol flow rate according to theoretical hydrating temperature (THT). To optimize methanol flow rate it is offered to use following algorithm of operational control. In order to detect THT temperature and pressure measurement are used. These meanings could be get in real time. If while monitoring gas temperature on the entrance of Gas Processing Plant is lower than THT, the additional testing is carried out. The dynamic of pressure changing on the entrance of Gas Processing Plant is checking. According to this we can increase methanol flow rate in case of the beginning of hydrating or correct THT using knowledge data base, but methanol flow rate remains the same. The offered algorithms of optimal control of methanol flow rate allows to improve the confidence level of diagnosis and to use methanol more reasonable.

Diagnosis

As a result of seal failure in the gas reservoir-well system due to some geological or technical factors, gas leaks to the areas beyond underground gas storage limits may occur, mainly behind casing via channels in the cement. In view if this, timely well integrity diagnostics become especially important.
This paper deals with a case where behind-casing gas flow was detected in a well of the underground gas storage (UGS) by means of an integrated logging data analysis. Spectral noise logging (SNL), high-precision temperature logging (HPT), and pulsed neutron logging (PNL) methods were used for identification of behind-casing flows. For example, the high sensitivity spectral noise logging tool captured acoustic signals in a wide frequency band, which were interpreted to occur in the intervals of gas flows through permeable formations. It was also found that gas from the underground gas storage was escaping to the overlying and underlying permeable formations. Based on the correlation with CBL data which showed a poor cement bond, it was concluded that this communication took place through the casing annulus. The high-precision temperature logging determined the direction of these behind-casing flows to be upwards and downwards from the UGS. Numerical estimation of gas volumes in the formations where gas injection tales place and occurrence of gas in cement cracks and micro gaps was carried out using pulsed neutron-neutron logging. In addition, the MID and spinner data confirmed the absence of any integrity problems in tubing and production casing strings.

ENERGY SECTOR

In the context of the implementation in Russia of Federal Law No. 261 “On energy saving and energy efficiency improvements and on Amendments to certain Legislative Acts of the Russian Federation” dated 23.11.2009 Gazprom PJSC established and continuously operated an energy saving management system.

Energy saving, as a multi-phase and multi-parameter space, where architecture is dynamically and constantly changes, stipulates the necessity of technical-organizational and process modernization of the management system in order to reduce the entropy and quasientropy processes in the system and its structural components.

In order to improve the sustainability and survivability of energy management system of Gazprom PJSC the paper presents the developed functionality, providing reduction of entropy and quasi-entropy processes in the hierarchical system and its structural components, and generated proposals for its improvement. The proposed set of measures will enable the effective implementation of energy-saving policy of Gazprom PJSC at the current and future conditions in the period until 2035.

Geology

The deposits of South-West Uzbekistan are located in the northeastern part of the Amu-Darya oil and gas provinces. The previously studied information was analyzed and new data from recent years was studied. It makes possible to establish the main geological features of the region, to clarify the oil and gas potential and paleographic conditions, and to create (offer) a classification of fields, based on the type of natural reservoir.
The region is well-studied currently. The deposits of South-West Uzbekistan belong tectonically to Chardzhou and Bukhara steps. Due to their nature these deposits are belong to the oil and gas area of the same name which one of the largest oil and gas potential within the basin.
Gas and gas condensate fields are dominated within the province. Oil fields and margin can be noted only on 19% of all discovered oil and gas Amu-Darya basin.
The gas containing deposits are belong stratigraphically to periods from the Lower Jurassic to Upper Cretaceous. Notable influence on the formation of oil and gas deposits had an Upper Jurassic salt-anhydride formation. The gas content of Cretaceous sediments can be observed only outside.
After researching of collected information, and based on the geological conditions of sedimentation and region’s tectonic features and certain fields, the classification of South-West Uzbekistan deposits was invented, depending on the type of natural reservoir. The deposits can be divided to two major groups – the fields related to formation type natural reservoir and fields related to massive type natural reservoir.

Babaev A.G. To knowledge of the genetic background for the oil and gas content and gas content of the Lower and Middle Jurassic deposits of the Central Asia [K poznaniiu geneticheskikh predposylok neftegazonosnosti i gazonosnosti nizhne- i sredneiurskikh otlozhenii Srednei Azii]. Geology of the oil and gas fields in West and South Uzbekistan [Geologiia neftianykh i gazovykh mestorozhdenii Zapadnogo i Iuzhnogo Uzbekistana]. Collection of essays. SAIGIMS, Tashkent, 1972.

Dorofeev N.V. Modelling of the structure and formation of complicated structure of the oil and gas deposits and the risk minimization of their development [Modelirovanie stroeniia i formirovaniia slozhno postroennykh zalezhei nefti i gaza i minimizatciia riskov ikh osvoeniia]. Thesis ...Candidate of Science (Geology and Minerology). Stavropol, 2015.

﻿The most important step in the three-dimensional geological modelling is a conceptual geological model development, which reflects main geological principles of the deposit structure. The geological structure features of studied deposits should be fully taken into account in their three-dimensional geological and geophysical modelling to create proper geomodel of the studied object. To successfully predict the size and shape of natural hydrocarbons reservoir and to draft the correct three-dimensional geological model it is necessary to study the process of deposition and tectonic development of the investigated area (conceptual model). The most important part of the conceptual geological model are sedimentation and tectonic models. It is in this particular aspect that the conceptual model is understood in this paper. Appropriately developed sedimentation model has a certain predictive potential, allowing for creation of a three-dimensional geological model even at a limited set of data in a rare well network at most of the productivity area. The object of research in this paper is the territory of Dulisminskiy licensed area, where the oil and gas field with the same name is discovered. For the studied object the paper represents the research results for all available core material, data of production well logging (PWL) and facies determination on their basis. The results of lithofacies analysis and paleogeographic reconstructions established the conditions for deposits formation of Yarakta horizon in the territory of Dulisminskiy licensed area. The developed lithofacies model of Yarakta horizon deposits allowed for identification of development patterns of reservoir zones with significantly different thickness, geological structure and quality. The proposed sedimentation model is used for three-dimensional geological model development of Yarakta horizon.

OIL AND GAS PRODUCTION

In the article the urgency of studying of oil-saturated rocks of the Bazhenov formation. Considered the advantages and disadvantages of thermo-gas reservoir stimulation during development. The described mechanism of thermal gas effect (HPAI). Comparative analysis of the geometrical changes of the sizes of the two core samples of the Bazhenov formation after exposure to high pressures and temperatures.
The study of the natural structure of the oil-bearing rocks of the Bazhenov formation, obtaining data for modeling the chemical reactions occurring in the species contained in the hydrocarbons for injection into the reservoir of air, requires the development and creation of new, specialized techniques and instruments of research.
The Bazhenov formation is a natural oil-bearing object that has a number of unexplored properties. To obtain data on many of these properties on a standard instrument is not possible. Direct transfer of known methods for the study of the Bazhenov formation is almost impossible. An additional complication in the description of the processes is imposed when using the method of DVT.

The article presents the results of laboratory testing for developed multifunctional composition combining water-soluble polymers and surface active agents (surfactants) as well as inorganic components (nanopowders Cu, Al), intended for extracting residual or HTR oil reserves.
The possibility of the reservoir hydrodynamic stimulation efficiency improvement was established under laboratory conditions, through the use of displacing compounds, developed on the basis of water-soluble surfactants, polymers and metal powders. Polyacrylamide was used as the water-soluble polymer, and the composition consisting of naphthenic acid salts and N-containing compounds was used as surfactant with cleaning and inhibiting properties. Used Al and Cu nanoparticles had the dimension of 50–70 nm. The oil from Gala field, Absheron Peninsula, Azerbaijan was analysed. This oil refers to oils of methane-naftene type and is characterized by low content of resinous- asphaltene substances (RAS). Experiments were carried out with a unit simulating a reservoir model. Sand from the well of this field was used as a filler of glass tube.
The results obtained indicate that the use of surfactants and metal nanopowders improve the properties of polyacrylamide as the oil displacement agent. Obviously, metal nanopowders have different effects on oil displacement factor. Nanopowder Al composition in this experiment was more effective than a nanopowder with Cu.

OIL AND GAS REFINING

Modernization is one of the key development processes for Russian oil refining industry, general condition of the complex depends on modernization efficiency level at each refinery. Engineering consists of the most important project implementation stages; engineering services market in Russia is currently in the state of development, thus the most topical issues for the market are: accomplishment of complex objectives of engineering, cooperation between Russian and foreign contractors. In the article criteria and indexes for measuring oil refineries revamp projects efficiency are considered, focusing on innovative technologies that increase conversion level, performance characteristics (i.e., energy consumption) and economic parameters (NPV, IRR and other). Choosing project implementation scheme that offers lower capital costs or higher profit than others is typical for oil companies. This scenario may finally lead to the option, in which operational expenses outstrip revenues from sales of products, due to increasing complexity and nonequivalence of revamp projects. Therefore decision-making process should be improved, taking into account industry requirements and particular characteristics of modernization (compared to grassroot construction projects). Certain conclusions regarding investment prospects of various modernization areas and revamping viability are drawn, based on project analysis. The aim is to create a universal list of criteria for estimation of such a project that would allow taking rational investment decisions. As a result, correlation between project parameters is proven as well as importance of complex approach to refining and petrochemical facilities revamp feasibility studies. Authors propose 2 main directions of project indexes change: revenue increase and cost cuts. From this point of view forecasting total effect on project economics becomes easier, more so if project analogues in Russia and CIS countries exist. Value of systematic project analysis perfomed prior to final investment decsion is expressed in significant budget savings, shorter construction period, lack of necessity to incorporate changes into project during engineering and procurement stages, and opportunity to decline custom-made equipment procurement and maximum use of local equipment instead.

PUMPS COMPRESSORS

The authors report the results of the control station bench tests by PNPPK JSC with Vacon variable speed drive NXP series for permanent magnet synchronous motors of wells sucker rod pumping units. The tests were performed by specialists of PNPPK JSC and EPU-ITC LLC. The purpose of inspection was an objective comparative evaluation of the presented equipment dynamic properties. The synchronous motor of VDPM-SC-470B type with permanent magnet excitation produced by NIPTIEM PJSC was used as a control object. During the tests, the following various equipment operation modes, which are most important in the actual operation, were reproduced and subject to evaluation: “soft start” mode; “the rotation speed stabilization at the preset operator level” mode; surging and dipping of the torque load mode, surging of the mains voltage (jump up) mode. In all stationary modes the equipment demonstrated steady work. There was a stable rotation speed when operating in the range of mains voltages below the nominal. The rotation speed stabilization in the specified range is assured by the special control algorithm of the Vacon variable speed drive (field weakening mode), which allows keeping the control characteristics of the drive stable when the mains voltage dips (the rotation speed stabilization set by the operator) to the level of 285 V (–25%). In dynamic modes caused by perturbations (such as: abrupt and trapezoidal change in load torque, intermittent dips and jumps of the supply voltage), transient processes (in the form of jumps and dips of currents, voltages, rotation speeds) are practically absent due to the high response speed of the control station. Thus, the use of the permanent magnet synchronous motors in combination with the control algorithms of oil production technological processes, already implemented in the intellectual control stations, including the production facilities of PNPPK JSC [4, 5], can greatly reduce the expenses of oil companies and make a significant contribution to energy savings.

Pipelines exploitation and repair

Concrete coated pipe appliance provides workability during construction and overhaul as well as stable design position of submerged crossing. Concrete coated pipe appliance also improves performance of submerged crossing.
The use of concrete coated pipes eliminates process steps for installation lining coating and weighting ring, stacking ease conditions by dragging on the bottom (to reduce friction, reduce the required tractive effort).
However, it should be noted that there is no data about friction factors of concrete coated pipes in technical standards, with different types of surface coatings, which creates difficulties of application in the development of design documentation.
Sliding friction factor is an essential element both in pipeline dragging traction and shift from hydrodynamic flow pressure of the water calculations in design process.
Technique has been offered of determining sliding friction factor concrete coated pipes with various types of surface coatings within of this work.
The research is based on the use of mobile model a small copy of concrete coated pipe and fixed base of soil, located in the hydrometrical flumes.
The developed method defines the procedure for the following research: measurement of force sliding friction concrete coated pipe, determination of sliding friction factor of concrete coated pipe.
The article reveals technique of determining sliding friction factor of concrete coated pipe produced at Moscow Pipe-coating Plant OJSC and Pipeline Coating and Technologies LLC. Concrete coated pipes are used at overhaul and constructional works in Gazprom PJSC.
Results of the research are intended to improve the quality of design, construction and overhaul on submerged crossings using these products.

Creation of a pilot study of the hydrological tray and investigation of the river underwater pipeline free flight drag forces dependence on the size of the gap between the pipe and the bottom of the river [Sozdanie e'ksperimental'nogo gidrologicheskogo lotka i issledovanie na nem zavisimosti sily lobovogo soprotivleniya svobodnogo proleta rechnogo podvodnogo truboprovoda ot velichiny prosveta mezhdu truboprovodom i dnom reki]. Report on research work. Orgenergogaz OJSC, Moscow, 2011.